From: Timo Sirainen <timo.sirainen@open-xchange.com>
Date: Thu, 11 Mar 2021 23:23:04 +0000 (+0200)
Subject: lib: Optimize str_append_tabescaped_n()
X-Git-Tag: 2.3.17~100
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=1abeccbecaa45898b1e0d3676c974fe8b6ef5727;p=thirdparty%2Fdovecot%2Fcore.git

lib: Optimize str_append_tabescaped_n()
---

diff --git a/src/lib/strescape.c b/src/lib/strescape.c
index 99894651ca..73489cad84 100644
--- a/src/lib/strescape.c
+++ b/src/lib/strescape.c
@@ -103,33 +103,34 @@ int str_unescape_next(const char **str, const char **unescaped_r)
 
 void str_append_tabescaped_n(string_t *dest, const unsigned char *src, size_t src_size)
 {
+	size_t prev_pos = 0;
+	char esc[2] = { '\001', '\0' };
+
 	for (size_t i = 0; i < src_size; i++) {
 		switch (src[i]) {
 		case '\000':
-			str_append_c(dest, '\001');
-			str_append_c(dest, '0');
+			esc[1] = '0';
 			break;
 		case '\001':
-			str_append_c(dest, '\001');
-			str_append_c(dest, '1');
+			esc[1] = '1';
 			break;
 		case '\t':
-			str_append_c(dest, '\001');
-			str_append_c(dest, 't');
+			esc[1] = 't';
 			break;
 		case '\r':
-			str_append_c(dest, '\001');
-			str_append_c(dest, 'r');
+			esc[1] = 'r';
 			break;
 		case '\n':
-			str_append_c(dest, '\001');
-			str_append_c(dest, 'n');
+			esc[1] = 'n';
 			break;
 		default:
-			str_append_c(dest, src[i]);
-			break;
+			continue;
 		}
+		str_append_data(dest, src + prev_pos, i - prev_pos);
+		str_append_data(dest, esc, 2);
+		prev_pos = i + 1;
 	}
+	str_append_data(dest, src + prev_pos, src_size - prev_pos);
 }
 
 void str_append_tabescaped(string_t *dest, const char *src)
diff --git a/src/lib/test-strescape.c b/src/lib/test-strescape.c
index b918062d1d..5b1323200a 100644
--- a/src/lib/test-strescape.c
+++ b/src/lib/test-strescape.c
@@ -10,6 +10,7 @@ struct strinput {
 };
 
 static const char tabescaped_input[] = "\0011\001t\001r\001nplip\001n";
+static const char tabescaped_input_with_nul[] = "\0011\001t\001r\001nplip\001n\0010";
 static const char tabunescaped_input[] = "\001\t\r\nplip\n";
 
 static const char *wrong_tabescaped_input = "a\001\001b\001\nc\0011\001t\001r\001nplip\001n";
@@ -133,6 +134,12 @@ static void test_tabescape(void)
 	str_append_tabescaped(str, tabunescaped_input);
 	test_assert(strcmp(str_c(str), tabescaped_input) == 0);
 
+	/* test escaping the trailing NUL as well */
+	str_truncate(str, 0);
+	str_append_tabescaped_n(str, (const unsigned char *)tabunescaped_input,
+				strlen(tabunescaped_input)+1);
+	test_assert_strcmp(str_c(str), tabescaped_input_with_nul);
+
 	/* unescaping */
 	str_truncate(str, 0);
 	str_append_tabunescaped(str, tabescaped_input, strlen(tabescaped_input));